The present invention relates to a tension device of a chain in a chain saw.
In a conventional chain tension device mounted on a chain saw, adjustment screws are provided parallel with a longitudinal guide bar, and the tension of a chain is adjusted by loosening or tightening the adjustment screws to move the guide bar. In another chain tension device, as proposed in the Japanese Utility Model Application laid-open No. Sho 61-93201, a rod member is disposed along a chain tensioning direction, engaged with a guide bar, and biased by a compression spring in the chain tensioning direction, so that the tension of a chain is properly adjusted.
In the former chain tension device, however, the adjustment screws need to be laboriously loosened or tightened in the guide bar with a screw driver or the like. Further, it is difficult to properly adjust the tension of the chain without applying excessive or insufficient tension to the chain. In the latter chain tension device, since the rod member is provided in the longitudinal direction, the number of components is increased, a compact structure cannot be obtained, and the attachment of the rod member itself is laborious.